Effect of A-Site Cation on Photoluminescence Spectra of Single Lead Bromide Perovskite Nanocrystals.
basic_science · Level V
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- Record sourced from PubMed, PMID 32330045.
- Also identified by DOI 10.1021/acs.nanolett.0c01417.
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Abstract
Lead halide perovskite (APbX<sub>3</sub>) nanocrystals exhibit photoluminescence (PL) with both wide wavelength tunability and high quantum efficiency. While the Pb-X<sub>6</sub> octahedra mainly determines the near-band-edge optical properties and the A-site cation affects the structural stability, the role of the A-site cation in determining the optical properties is still unclear. Here, we report the PL properties of three types of lead bromide perovskite APbBr<sub>3</sub> nanocrystals with different cations [A = HC(NH<sub>2</sub>)<sub>2</sub><sup>+</sup>, CH<sub>3</sub>NH<sub>3</sub><sup>+</sup>, and Cs<sup>+</sup>], as revealed by single-dot spectroscopy, and discuss the influence of the A-site cation on the PL spectrum. The nanocrystal size dependences of the PL energy and lifetime show no large variation with the species of the A-site cation. We find that the size of the A-site cation determines the coupling strength between electrons and longitudinal-optical phonons in the nanocrystal and thus affects the PL spectral shape, especially the low-energy tail.